COBOL_Training_Class-14.ppsx

7/27/2019 COBOL_Training_Class-14.ppsx

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IBM MAINFRAMES

COBOL Training Class-10


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Introduction to COPY Stat!nt

A COPYstatement is used to bring a series of prewritten

COBOL entries that have been stored in library, into a

program.

These are used at Common routines like error routine, date validation

routine are oded in a library and bring into the program

by COPY.

!aster files are used in multiple programs. Their layoutan be plaed in one opyboo" and be plaed wherever the

files are used. #t promotes program standardi$ation sine all

the programs share the same layout and the same data

names. !ostly %now asCOPYBOOK


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Introduction to COPY Stat!ntcontd""

Copyboo"s are stored as members in P&' library

and during ompilation time, they are inluded into

the program.

By default, the opyboo" library is 'Y'L#B.

Copyboo"s an be used in

ENVIRONMENT IVI!ION

"T" IVI!ION

PROCE#RE IVI!ION$


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Pur#os O$ COPY Stat!nt

This redues oding and debugging time. Change in

layout needs hange in opyboo" only. #t is enough if

we (ust reompile the program for ma"ing the new

opy effetive.

'ynta)*

COPY opyboo"+name

-PLAC#/0string+to+be+replaed BY replaing+

string1


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R#lacing o#tion %it& COPY

One opyboo" an be used with -PLAC#/0verb to replae

high+level 2ualifier of the all the variables with another

2ualifier.

)ample*COPY C3'TO!- -PLAC#/0 4C3'T5+4 BY 4C3'T6+4.

&elimiter %& &' should be used for replaing pseudo te)ts. The

replaing option does not alter the prewritten entries in the

library7 the hanges are made to the user8s soure program

only.


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Introduction to CALL Stat!nt

9hen a speifi funtionality need to be performed in more

than one program, it is best to write them separately and all

them into eah program.

The mainprogramthat referenes or alls a subprogram is

referred to as the allingprogram. The subprogramthat is

lin"ed and e)euted within the main program is referred to as

the alled program.


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Main Progra! in 'tails

Main Pro(ram

CALL statement is used for e)euting the sub+program from the

main program. A sample of CALL statement is given below*

C")) %P*MN"ME+' #!IN*BY REERENCE -!.V"R+,

BY CONTENT -!.V"R/$

P0!/A!5is alled here. 9'+:A-5 and 9'+:A-6 are

wor"ing storage items. 9'+:A-5 is passed by referene. 9'+:A-6 is passed by Content. BY -;-/C is default in

COBOL and need not be oded.


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Pass B( R$rnc ) Pass B( Contnt

BY REERENCE BY CONTENT

Call 4P0!/A!8 3'#/0BY -;-/Cws+var5.

Call 4P0!/A!8 3'#/0BY CO/T/Tws+var5.

#t is default in COBOL BY CO/T/T "ey word isre2uired

"ddressof ws+var5 is passed Valueof ws+var5 is passed

The sub+program

modifiations on the passedelements are visiblein themain program.

The sub+program

modifiations on the passedelements are loal to thatsub+program and notvisi0lein the main program.


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Su* Progra! in 'tails

PRO*R"M.I. COBOL?@ feature.

Alternatively C"NCE)issued after CALL, will set the sub+

program to initial state.

#f the sub program is modified then it needs to be reompiled.

The need for main program reompilation is deided by theompiler option used for the main program.

#f the YN"Mompiler is used, then there is no need to

reompile the main program. NOYN"Mis default that

e)pets the main program reompilation.


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Su* Progra! in 'tailscond""

L#/%A0'CT#O/is used to define all the reeiving data

items .

P-OC&3-:#'#O/3'#/0L%+:A-5,L%+:A-6

There is a one+one orrespondene between passed elementsand reeived elements BYPO'#T#O/. This implies that the

name of the identifiers in the alled and alling program need

not be the same >9'+:A-5 L%+:A-5 but the number of

elements and piture lause should be same. The last statement of your sub+program should be #T

P-O0-A!D0OBAC%. This returns the ontrol ba" to main

program. 3se 0OBAC% but not 'TOP-3/.


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'i$$rnc B+, Static ) '(na!ic CALL

#dentified by CALL literal

E12 C")) %PRO*N"ME'$

&efault ompiler option is

/O&Y/A!

#f subprogram undergoes

hanges main program subprogram both should be

reompiled

#dentified by variableshould

be populated at run time.

E32 C")) -!.PR*N"ME.

Compiler option is &Y/A!

-eompilation of subprogram

is enough


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Static ) '(na!ic Cond""

'ub modules are lin" edited

with main module

'i$e of load module is lar(e

astaess

)ess4le1i0le

9ill not be in initial state

the ne)t time it is alled

unless e)pliitly useINITI")O- CA/CL

after eah CALL

'ub modules are pi"ed up

during run

Load si$e is less

!lo5 ompared to stati

Morefle)ible

9ill be in initial state every

time it alled.


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MAIN PRORAM

IDENTIFICATION DIVISION.PROGRAM-ID. MAINPGM.

ENVIRONMENT DIVISION.

DATA DIVISION.

WORKING-STORAGE SECTION.

01 Sales-Data. 05 WS-NO-UNITS PIC 9(!.

05 WS-COST PIC 9("!V9(#!.

05 WS-AMNT PIC 9($!V9(#!.

01WS-PGMNAMEPIC %(0&! VA'UE SU)PROG*.

PROCEDURE DIVISION.100-MAIN-'OGIC.

ACCEPTWS-NO-UNITS. ACCEPT WS-COST.ACCEPTWS-AMNT.

CA'' SU)PROG*+WS-PGMNAMEUSINGWS-NO-UNITS,WS-COST ,WS-

AMNT. STOP RUN.


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S.B PRORAM

IDENTIFICATION DIVISION.

PROGRAM-ID. SU)PROG IS INITIA' PROGRAM.

ENVIRONMENT DIVISION.

DATA DIVISION.

WORKING-STORAGE SECTION.

'INKAGE SECTION.

01 'S-Sales-Data.

05 'S-NO-UNITS PIC 9(!.

05 'S-COST PIC 9("!V9(#!.

05 'S-AMNT PIC 9($!V9(#!.

PROCEDURE DIVISION USING 'S-NO-UNITS'S-COST'S-AMNT.

100-MAIN-'OGIC.

DISP'A 'S-SA'ES-DATA.

GO)ACK.


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PARM Para!tr

#t is used to aess the data that are e)ternal to the program.

ECL an send ma)imum 5FF haraters to a program thru

PA-!.

Lin"age setion !3'T be oded with a hal4 5ord 0inary4ield, prior to atual field. #f length field is not oded, the first

two bytes of the field oded in the lin"age setion will be filled

with length and so there are hanes of 6 bytes data trunation

in the atual field.F5 L%+&ATA.

F@ L%+L/0TG P#C 'H>FI CO!P.

F@ L%+:A-#ABL P#C >F?.


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T&an/ You

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COBOL_Training_Class-14.ppsx